TWI477538B - Liquid crystal aligning agent and liquid crystal display element - Google Patents

Description

Liquid crystal alignment agent and liquid crystal display element

The present invention relates to liquid crystal alignment agents and liquid crystal display elements. More specifically, in particular, when it is used in a horizontal electric field display type liquid crystal display element, it is possible to provide a liquid crystal alignment agent which is excellent in a dark state display when an electric field is not applied, and a liquid crystal display element.

A liquid crystal display element in which an electrode is formed only on one side of a pair of substrates disposed oppositely, and an electric field is generated in a direction parallel to the substrate, for example, an IPS (in-plane switching) mode or an FFS (Fringe Field Conversion) mode. It is known that an electrode is formed on both substrates, and a conventional vertical electric field type liquid crystal display element which generates an electric field in a direction perpendicular to the substrate has a wide viewing angle property and can be displayed with high quality. The liquid crystal display element of the horizontal electric field display mode is described, for example, in Patent Documents 1 and 2 and Non-Patent Document 1. In the liquid crystal display device of the horizontal electric field type, since the liquid crystal molecules respond to the electric field only in the direction parallel to the substrate, there is no problem in the refractive index change in the long-axis direction of the liquid crystal molecules, and the contrast confirmed by the observer and the concentration of the display color even when the viewing angle is changed. The change is small, so that high quality display can be performed from an unrestricted angle.

The horizontal electric field type liquid crystal display element has the object of reducing power consumption based on further improving display performance and improving utilization efficiency of the backlight, and requires a ratio of transmittance in a dark state to a bright state when the component is switched between the applied and applied electric fields (contrast Large liquid crystal display elements.

Wherein, the transverse electric field type liquid crystal display element having the liquid crystal layer in the antiparallel alignment state between the two polarizing plates disposed in the orthogonal polarizer is in a dark state when no electric field is applied, the alignment axis of the liquid crystal and the first polarizing plate When the polarization axes are the same, the linearly polarized light passing through the liquid crystal layer passes through the liquid crystal layer without disturbing the phase thereof, and the transmitted light ensures the black display by blocking the second polarizing plate disposed in parallel with the first polarizing plate. At this time, when the alignment of the liquid crystal and the polarization axis of the polarizing plate are not disturbed, the linearly polarized light that has passed through the liquid crystal layer forms circularly polarized light (or elliptically polarized light), and a part of the polarized light passes through the second polarizing plate to cause light leakage.

Therefore, there is an urgent need to develop a liquid crystal alignment film which realizes a uniaxial alignment of liquid crystal with high precision. In the past studies, attempts have been made to improve the uniaxial alignment of liquid crystal molecules by using a polyimine synthesized from an aromatic tetracarboxylic dianhydride and an aromatic diamine (Non-Patent Document 2). However, with this technique, satisfactory results were obtained which improved the dark state when no electric field was applied.

Further, in the lateral electric field type liquid crystal display device, there is a problem of image sticking and burn-in, and improvement is desired. In this regard, Patent Document 6 proposes a method of improving the afterimage property and the burn-in property by using a liquid crystal alignment film formed of a polymer having a large proportion of an aromatic structure. However, if a liquid crystal alignment film containing an aromatic structure in a large proportion is used, the pretilt angle is inevitably increased, and the advantageous effects as described above in the lateral electric field type display element are eliminated.

In the horizontal electric field type liquid crystal display element, the above advantageous effects can be sufficiently exhibited, and a liquid crystal display element which can provide a liquid crystal alignment film which exhibits improved afterimage properties and burn-in properties is still unknown, and it is strongly desired to provide such a liquid crystal. An aligning agent.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] US Patent No. 5,958,333

[Patent Document 2] Japanese Laid-Open Patent Publication No. SHO 56-91277

[Patent Document 3] Japanese Patent Laid-Open No. Hei 6-222366

[Patent Document 4] Japanese Patent Laid-Open No. Hei 6-281937

[Patent Document 5] Japanese Patent Laid-Open No. Hei 5-170044

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2008-15497

[Patent Document 7] Japanese Patent Laid-Open Publication No. 2010-97188

[Non-patent literature]

[Non-Patent Document 1] "Liq. Cryst.", vol. 22, p379 (1996)

[Non-Patent Document 2] "Functional Materials", vol. 27, p69 (2007)

The present invention has been made in view of the above problems, and an object thereof is to provide a liquid crystal alignment agent which can provide a liquid crystal alignment film which effectively exerts an advantageous effect of a lateral electric field type liquid crystal display element while not The light transmittance in the dark state where the electric field is applied is lowered, and the image retention property is excellent; and the liquid crystal display element having a large contrast is provided.

Other objects and advantages of the invention are indicated by the following description.

According to the present invention, the above object of the present invention is first achieved by a liquid crystal alignment agent characterized by containing at least one polymerization selected from the group consisting of polyproline and polyimine. The above-mentioned polymer has a structure represented by the following formulas (1) and (2) simultaneously in at least a part of its molecule.

(In the formula (1), R ¹ each independently represents an alkyl group having 1 to 6 carbon atoms, and R ² each independently represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, a cyano group, a hydroxyl group or a carboxyl group. n is an integer of 1 to 10, a each independently represents an integer of 0 to 4, "*" represents a linkage; in the formula (2), R ³ represents an alkyl group having 1 to 6 carbon atoms, and each of R ⁴ Independently represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, a cyano group, a hydroxyl group or a carboxyl group, b represents an integer of 0 to 5, c represents an integer of 0 to 4, and d represents an integer of 0 to 3, "* "" indicates the connection key).

The above object of the present invention, the second object, is achieved by a liquid crystal display element having a liquid crystal alignment film formed of the above liquid crystal alignment agent.

The liquid crystal alignment agent of the present invention can form a liquid crystal alignment film which effectively exerts an advantageous effect of a lateral electric field type liquid crystal display element, and at the same time, can reduce light transmittance in a dark state when no electric field is applied, and further has Excellent afterimage properties. The liquid crystal display element of the present invention having the liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention has a large contrast ratio and is excellent in image sticking properties.

The liquid crystal alignment agent of the present invention is therefore suitably used for a liquid crystal alignment film for forming a lateral electric field type liquid crystal display device, and is also suitable for various other liquid crystal display elements such as a TN type, an STN type, and a VA type.

The liquid crystal display element of the present invention can be effectively applied to various devices, for example, in watches, portable game machines, word processors, notebook computers, navigation systems, video cameras, video recorders, PDAs, digital cameras, mobile phones, various monitors. Used in display devices such as LCDs and LCD TVs.

Hereinafter, the present invention will be described in detail.

The liquid crystal alignment agent of the present invention contains at least one polymer selected from the group consisting of polylysine and polyamidiamine, wherein the polymer has both the above formula (1) and (at least a part of its molecule) 2) The structure represented separately. In the present specification, such a polymer is hereinafter referred to as "specific polymer". In the specific polymer, the structure represented by the above formula (1) may be present in the main chain of the polymer, may be present in the side chain of the polymer, or may be present in both the main chain and the side of the polymer. In the chain, the structure represented by the above formula (2) may be present in the main chain of the polymer, may be present in the side chain of the polymer, or may be present in both the main chain and the side chain of the polymer.

R ¹ in the above formula (1) is preferably an alkyl group having 1 to 3 carbon atoms, particularly preferably a methyl group. The alkyl group having 1 to 6 carbon atoms of R ² is preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group. a is preferably 0 each. n is preferably from 1 to 4, more preferably from 2 to 4.

R ³ in the above formula (2) is preferably an alkyl group having 1 to 3 carbon atoms, particularly preferably a methyl group. The alkyl group having 1 to 6 carbon atoms of R ² is preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group. b is preferably an integer of 1 to 5, more preferably 3, and particularly preferably b is 3 and the substitution positions of the three groups R3 are at the 1,3,3-position of the anthracene ring. c and d are each preferably 0. The pendant phenyl group (optionally having a group R ⁴ ) is preferably attached to the 1-position of the indane ring.

The specific polymer in the present invention preferably contains the structure represented by the above formula (1) in the range of 0.001 to 0.002 mol/g; preferably contains the structure represented by the above formula (2) in the range of 0.0002 to 0.001 mol/g. A polylysine having a structure represented by the above formulas (1) and (2) as described above, at least a part of the molecule, for example, which can be obtained, for example, comprising a structure represented by the above formula (1) and two carboxy groups. An acid anhydride group-containing compound and a tetracarboxylic dianhydride having both a structure represented by the above formula (2) and a compound having two carboxylic anhydride groups are reacted with a diamine or a tetracarboxylic dianhydride having the above formula (1) a structure obtained by reacting a diamine with two amine-based compounds and a compound having the structure represented by the above formula (2) and a compound of two amine groups; at least a part of the molecule has the above formula ( The polyimine of the structure represented by 1) and (2), respectively, can be obtained, for example, by dehydration ring closure of the polylysine obtained above.

The specific polymer contained in the liquid crystal alignment agent of the present invention is preferably at least one polymer selected from the group consisting of polylysine and polyamidene formed by dehydration of the polyglycolic acid, wherein Polylysine is obtained by reacting a tetracarboxylic dianhydride having a structure represented by the above formula (1) and two amine groups and having a structure represented by the above formula (2) and a diamine. Two of the two amine based compounds.

<polylysine>

As described above, the preferred polyglycolic acid in the present invention is obtained by reacting a tetracarboxylic dianhydride and a diamine, wherein the diamine comprises a compound having the structure represented by the above formula (1) and two amine groups, and Both the structure represented by the above formula (2) and the compound of two amine groups.

[tetracarboxylic dianhydride]

Examples of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid in the present invention include aromatic tetracarboxylic dianhydride, tetracarboxylic dianhydride having an aliphatic dicarboxylic acid anhydride structure, and an alicyclic group. A tetracarboxylic dianhydride having a dicarboxylic acid anhydride structure, a tetracarboxylic dianhydride having both an aliphatic dicarboxylic acid anhydride structure and an aromatic dicarboxylic acid anhydride structure. In addition, examples of the tetracarboxylic dianhydride having an aliphatic dicarboxylic acid anhydride structure include aliphatic tetracarboxylic dianhydride and the like; and tetracarboxylic dianhydride having an alicyclic dicarboxylic acid anhydride structure, An alicyclic tetracarboxylic dianhydride etc. are mentioned.

Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride and a compound represented by the following formula (T-1).

(In the formula (T-1), R ^{5 is} each independently an alkyl group having 1 to 6 carbon atoms, a halogen atom, a cyano group or a hydroxyl group, and e is each independently an integer of 0 to 3).

The alkyl group having 1 to 6 carbon atoms of R ⁵ in the above formula (T-1) is preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group. e is preferably 0 each. Specific examples of the compound represented by the above formula (T-1) include, for example, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetra Carboxylic dianhydride and the like.

Examples of the aliphatic tetracarboxylic dianhydride include butanetetracarboxylic dianhydride and the like. The tetracarboxylic dianhydride which has both the above-mentioned aliphatic dicarboxylic anhydride structure and the aromatic dicarboxylic acid anhydride structure, for example, a compound represented by the following formula (T-2), etc. are mentioned.

(In the formula (T-2), R ⁶ and R ⁷ are each independently an alkyl group having 1 to 6 carbon atoms, a halogen atom, a cyano group or a hydroxyl group, and f is an integer of 0 to 8, and g is 0 or 1 ).

The alkyl group having 1 to 6 carbon atoms of R ⁶ and R ⁷ in the above formula (T-2) is preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group. f and g are preferably 0, respectively. Specific examples of the compound represented by the above formula (T-2) include, for example, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-di-oxy-3) -furyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2 , 5-dioxy-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, and the like.

Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, and 3- Oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-di-oxo-4 Hydrogen-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:2,5 :6-dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, 4,9-dioxatricyclo[5.3.1.0 ^2,6 ] eleven carbon-3,5,8,10-tetraone and the like. In addition to the above, the tetracarboxylic dianhydride which is described in the patent document 7 (JP-A-2010-97188) can be used as a tetracarboxylic dianhydride which synthesizes the poly phthalic acid of the present invention, and can be selected from them. More than one of them.

Among them, preferred examples of the tetracarboxylic dianhydride having an alicyclic dicarboxylic acid anhydride structure include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 2,3. 5-tricarboxycyclopentyl acetic acid dianhydride.

The tetracarboxylic dianhydride used for synthesizing the polyamic acid in the present invention preferably comprises at least one selected from the group consisting of aromatic tetracarboxylic dianhydrides and tetracarboxylic acid selected from the group consisting of aliphatic dicarboxylic anhydride structures. An anhydride, a tetracarboxylic dianhydride having an alicyclic dicarboxylic acid anhydride structure, and at least one of a tetracarboxylic dianhydride having both an aliphatic dicarboxylic anhydride structure and an aromatic dicarboxylic anhydride structure.

In this case, the preferred use ratio, the more preferable use ratio, and the more preferable use ratio of each of the above tetracarboxylic dianhydrides to all of the tetracarboxylic dianhydrides are shown in the following tables.

By using a mixture of tetracarboxylic dianhydrides in the ratios shown in the above table, it is preferable to form a liquid crystal alignment film having more excellent liquid crystal alignment properties.

The tetracarboxylic dianhydride used for synthesizing the polyamic acid in the present invention is preferably constituted within the above range by at least one selected from the group consisting of aromatic tetracarboxylic dianhydrides and selected from aliphatic dicarboxylic acids. An acid anhydride structure of tetracarboxylic dianhydride, a tetracarboxylic dianhydride having an alicyclic dicarboxylic anhydride structure, and a tetracarboxylic dianhydride having both an aliphatic dicarboxylic anhydride structure and an aromatic dicarboxylic anhydride structure. At least one of which is free of other tetracarboxylic dianhydrides.

[diamine]

The diamine for synthesizing the preferred polyamine in the present invention comprises a compound having the structure represented by the above formula (1) and two amine groups, and a compound having the structure represented by the above formula (2) and two amine groups. Both.

Preferable examples of the compound having the structure represented by the above formula (1) and the two amine groups include a compound represented by the following formula (D-1), and the like, and a structure represented by the above formula (2) and A preferred example of the compound of the two amine groups is, for example, a compound represented by the following formula (D-2).

(R ¹ , R ² , n and a in the formula (D-1) are the same as defined in the above formula (1); respectively, R ³ , R ⁴ , b, c and d in the formula (D-2) Same as the definition in the above formula (2).)

The compound represented by the above formula (D-1) may, for example, be 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 4,4'. -[1,3-phenylenebis(1-methylethylidene)]bis(aniline), 4,4'-[1,4-phenylphenylbis(1-methylethylidene)] Among them, aniline and the like are particularly preferably 4,4'-[1,3-phenylphenylbis(1-methylethylidene)]bis(aniline).

The compound represented by the above formula (D-2) may, for example, be 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indan-5-amine, 1-(4) -Aminophenyl)-1,3,3-trimethyl-1H-indan-6-amine and the like.

As the diamine for synthesizing the polyphosphoric acid which is preferable in the present invention, only the compound represented by the above formula (D-1) and the compound represented by the above formula (D-2) may be used, or the above formula (D) may be used. The compound represented by the formula (1) and the compound represented by the above formula (D-2) are used together with other diamines.

Examples of the other diamine which can be used herein include an aliphatic diamine, an alicyclic diamine, an aromatic diamine, a diamine organic decane, and the like. Specific examples thereof include aliphatic diamines, and examples thereof include 1,1-m-xylenediamine, 1,3-propanediamine, 1,4-butanediamine, and 1,5-pentane. An amine, 1,6-hexanediamine, etc.; as the alicyclic diamine, for example, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), 1, 3-di(aminomethyl)cyclohexane; etc.; as the aromatic diamine, for example, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diamino group Diphenyl sulfide, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-di (trifluoromethyl)biphenyl, 2,7-diaminostilbene, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl Propane, 9,9-bis(4-aminophenyl)anthracene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-di(4- Aminophenyl)hexafluoropropane, 4,4'-(p-phenylenediisopropylidene)bis(aniline), 4,4'-(meta-phenylenediphenylene)bis(aniline) , 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,6-diaminopyridine, 3,4-diamine Pyridine, 2,4-diaminopyrimidine, 3,6-diaminopurine Pyridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6 -diaminocarbazole, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine 1,4-bis(4-aminophenyl)perazine , 3,5-diaminobenzoic acid, cholestyloxy-3,5-diaminobenzene, cholestyloxy-3,5-diaminobenzene, cholestyloxy-2,4 -diaminobenzene, cholesteneoxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate , 3,5-diaminobenzoic acid lanthanum alkyl ester, 3,6-bis(4-aminobenzylideneoxy)cholestane, 3,6-bis(4-aminophenoxy) Cholestane, 4-(4'-trifluoromethoxybenzylideneoxy)cyclohexyl-3,5-diaminobenzoate, 4-(4'-trifluoromethylbenzonitrileoxy) Cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 1,1 - bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenoxy)methyl)phenyl)- 4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-(4-heptylcyclohexyl)cyclohexane and the following formula (D- 3) the indicated compound, etc.;

(In the formula (D-3), X ¹ is an alkyl group having 1 to 3 carbon atoms, *-O-, *-COO- or *-OCO- (wherein, a bond having "*" and two Aminophenyl linkage), m1 is 0 or 1, m2 is an integer from 0 to 2, and h is an integer from 1 to 20.

Examples of the diamine organooxosiloxane include 3,3'-(tetramethyldioxane-1,3-diyl)di(propylamine), and the like, and Patent Document 7 (Japanese Patent) The diamine described in JP-A-2010-97188.

X ¹ in the above formula (D-3) is preferably an alkyl group having 1 to 3 carbon atoms, *-O- or *-COO- (wherein a bond having a "*" bond and a diaminophenyl group) connection). Specific examples of the group C _h H _2h+1 - may, for example, be methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-decyl , n-decyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nine Alkyl, n-icosyl, and the like. The two amine groups in the diaminophenyl group are preferably at the 2,4-position or the 3,5-position relative to the other groups.

Specific examples of the compound represented by the above formula (D-3) include, for example, dodecyloxy-2,4-diaminobenzene, tetradecyloxy-2,4-diaminobenzene, and ten Pentameryl-2,4-diaminobenzene, cetyloxy-2,4-diaminobenzene, octadecyloxy-2,4-diaminobenzene, dodecyloxy- 2,5-Diaminobenzene, tetradecyloxy-2,5-diaminobenzene, pentadecyloxy-2,5-diaminobenzene, hexadecyloxy-2,5-di Aminobenzene, octadecyloxy-2,5-diaminobenzene, a compound represented by the following formula (D-3-1) to (D-3-3), and the like.

A liquid crystal alignment agent of at least one polymer of a group consisting of polyphthalic acid and polyimine obtained by using a diamine containing the compound represented by the above formula (D-3) is suitable as a vertical alignment type liquid crystal alignment agent. .

In the above formula (D-3), it is preferable that m1 and m2 are not zero at the same time.

As other diamines, the above uses p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether. At least one selected from the group consisting of 3,3'-(tetramethyldioxane-1,3-diyl)bis(propylamine) is preferred.

The diamine for synthesizing the poly-proline in the present invention preferably contains 50 to 90 mol% of the compound represented by the above formula (D-1) with respect to all the diamines; and preferably 10 to 50 mol% of the above formula with respect to all the diamines. The compound represented by (D-2); preferably contains 40 mol% or less of the above other diamine relative to all of the diamine.

[Synthesis of polyglycine]

The polyproline in the present invention can be reacted with a diamine such as the above-described tetracarboxylic dianhydride and a compound represented by the above formula (D-1) and a compound represented by the above formula (D-2). get.

The ratio of the tetracarboxylic dianhydride and the diamine used for the synthesis reaction of polylysine is such that the acid anhydride group of the tetraacid diamine is preferably 0.2 to 2 equivalents based on 1 equivalent of the amine group of the diamine. More preferably, it is a ratio of 0.7 to 1.2 equivalents.

The synthesis reaction of polylysine is preferably carried out in an organic solvent, preferably at -20 ° C to 150 ° C, more preferably at a temperature of 0 to 100 ° C, preferably for 1 to 72 hours, more preferably for 3 to 3 hours. 48 hours. Here, the organic solvent is not particularly limited as long as it can dissolve the produced polyamic acid, and examples thereof include 1-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-. Dimethylformamide, 3-butoxy-N,N-dimethylpropanamide, 3-methoxy-N,N-dimethylpropanamide, 3-hexyloxy-N,N - aprotic compounds such as guanamine compounds such as dimethylpropionamide, dimethyl hydrazine, γ-butyrolactone, tetramethyl urea, hexamethylphosphonium triamine; m-cresol, xylenol, A phenolic compound such as phenol or halogenated phenol. The amount of the organic solvent (α: when used together with the poor solvent described later means the total amount of the organic solvent and the poor solvent) is the total amount (β) of the tetracarboxylic dianhydride and the diamine relative to the total amount of the reaction solution The amount (α + β) is preferably an amount of from 0.1 to 30% by weight.

The organic solvent may be used together with an alcohol, a ketone, an ester, an ether, a halogenated hydrocarbon, a hydrocarbon, or the like which is confirmed as a poor solvent of polyglycolic acid, within a range in which the produced polyamic acid is not precipitated. Specific examples of the poor solvent include methanol, ethanol, isopropanol, cyclohexanol, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol, propylene glycol, and 1,4-butane. Alcohol, triethylene glycol, ethylene glycol monomethyl ether, ethyl lactate, butyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, A Methoxy propionate, ethyl ethoxy propionate, diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene Alcohol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene Alcohol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetrahydrofuran, Dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene , diisobutyl ketone, isoamyl propionate, isobutyl Isopentyl, diisoamyl ether.

When the organic solvent is used together with the poor solvent as described above, the amount of the poor solvent may be appropriately set within the range in which the produced polyamic acid is not precipitated, but the total amount with respect to the solvent is preferably 30% by weight. Hereinafter, it is more preferably 20% by weight or less.

The reaction solution can be directly used for preparing a liquid crystal alignment agent, or can be used for preparing a liquid crystal alignment agent after separating the polyamic acid contained in the reaction solution, or purifying the separated polyamic acid to prepare a liquid crystal alignment. Agent. When polypyridic acid is dehydrated and closed to form a polyimine, the above reaction solution can be directly used for the dehydration ring closure reaction, or the polylysine contained in the reaction solution can be separated and used for dehydration ring closure reaction, or separated. Poly-proline is used for dehydration ring closure after purification. The separation of the polyamic acid can be carried out by injecting the above reaction solution into a large amount of a poor solvent to obtain a precipitate, and drying the precipitate under reduced pressure; or by subjecting the organic solvent in the reaction to distillation under reduced pressure by an evaporator. Alternatively, it may be obtained by dissolving the polylysine in an organic solvent and then precipitating it in a poor solvent; or by repeatedly dissolving the polylysine in an organic solvent one or more times. After the solvent, the polyamine acid is purified by a method of distilling off the organic solvent contained in the washed solution by an evaporator under reduced pressure.

<polyimine]

The polyimine which can be a specific polymer which can be contained in the liquid crystal alignment agent of the present invention can be obtained by dehydration ring closure of the polyamic acid as described above.

The tetracarboxylic dianhydride used for the synthesis of the above polyimine may be the same as the tetracarboxylic dianhydride used in the synthesis of the above polyamic acid, and the preferred one is also polyamine. The same applies to the tetracarboxylic dianhydride used in the synthesis of an acid.

The diamine used for the synthesis of the polyimine contained in the liquid crystal alignment agent of the present invention may be the same diamine as the diamine used in the synthesis of the above polyamic acid.

The polyimine in the present invention may be a fully sulfhydryl imide which has a dehydration ring structure in which the proline structure of the polylysine which is a raw material is dehydrated; or a part of the structure of the proline may be dehydrated and closed to form a part. A partial ruthenium imide of a proline structure and a quinone ring structure. The polyimine in the present invention preferably has a ruthenium iodide ratio of 40 mol% or more, more preferably 80 mol% or more. By using a polyimine having a ruthenium iodide ratio of 40 mol% or more, it is possible to form a liquid crystal alignment agent which can provide a liquid crystal alignment film of a liquid crystal display element which exhibits higher contrast.

The above ruthenium amination ratio is a ratio indicating the number of the quinone ring structure in the percentage of the number of the guanine structure of the polyimine and the total amount of the quinone ring structure. At this time, a part of the quinone ring may be an isoindole ring. The ruthenium imidization rate can be obtained by dissolving the polyimine in a suitable heavy hydrogenation solvent (for example, dimethyl hydrazine), using tetramethyl decane as a reference material, from room temperature (for example, 25 ° C). The results of the ¹ H-NMR measurement were determined according to the following formula (1).

Yttrium imidation rate (%) = (1-A ¹ /A ² ×α)×100 (1)

In the mathematical formula (1), A ¹ is a peak area of a proton derived from an NH group which appears near a chemical shift of 10 ppm, A ² is a peak area from other protons, and α is the number of other protons relative to one polyfluorene. The proportion of protons of the NH group in the precursor of the amine (polyproline).

The dehydration ring closure of polylysine is preferably (i) by heating the polyamic acid, or (ii) dissolving the polylysine in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution. It is carried out according to the method of heating required.

The reaction temperature in the method of heating the polyamic acid of the above (i) is preferably from 50 to 200 ° C, more preferably from 60 to 170 ° C. The reaction time is preferably from 1 to 8 hours, more preferably from 3 to 5 hours. When the reaction temperature is less than 50 ° C, the dehydration ring closure reaction cannot be sufficiently performed; if the reaction temperature exceeds 200 ° C, the molecular weight of the obtained polyimide may be lowered.

On the other hand, in the method of adding a dehydrating agent and a dehydration ring-closure catalyst to the solution of the poly-proline in the above (ii), examples of the dehydrating agent include acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride. . The amount of the dehydrating agent to be used is preferably from 0.01 to 20 mol based on the desired guanidine imidization ratio with respect to 1 mol of the proline structure of the polyglycolic acid. Further, examples of the dehydration ring-closure catalyst include tertiary amines such as pyridine, trimethylpyridine, lutidine, and triethylamine. However, it is not limited to this. The amount of the dehydration ring-closure catalyst is preferably 0.01 to 10 mol based on 1 mol of the dehydrating agent to be used. The amount of the above dehydrating agent and the dehydration ring-closure catalyst may be higher, and the ruthenium ratio is higher. The organic solvent used for the dehydration ring-closure reaction may, for example, be an organic solvent exemplified as a solvent used for the synthesis of polyamic acid. The reaction temperature as the dehydration ring closure reaction is preferably from 0 to 180 ° C, more preferably from 10 to 150 ° C. The reaction time is preferably from 1 to 8 hours, more preferably from 3 to 5 hours.

In the method (ii), a reaction solution containing polyienimine can be obtained as above. The reaction solution can be directly used for preparing a liquid crystal alignment agent, or can be used for preparing a liquid crystal alignment agent after removing a dehydrating agent and a dehydration ring-closing catalyst from the reaction solution; and can also be used for preparing a liquid crystal alignment agent after separating the polyimine. Or after the isolated polyimine is refined, it is used to prepare a liquid crystal alignment agent. In order to remove the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution, for example, a method such as solvent replacement is suitably employed. The separation and purification of the polyimine can be carried out by the same operation as described above for the separation and purification method of polyglycine.

[End modified polymer]

The polyproline and polyimine in the present invention may each be a terminally modified polymer having a molecular weight adjusted. By using the terminal-modified polymer, the coating property and the like of the liquid crystal alignment agent can be further improved without impairing the effects of the present invention. Such a terminal-modified polymer can be produced by adding a molecular weight regulator to a polymerization reaction system when synthesizing polyglycolic acid. The molecular weight modifier may, for example, be an acid monoanhydride, a monoamine compound or a monoisocyanate compound.

Examples of the acid monoanhydride include maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl salicylic anhydride, n-dodecyl salicylic anhydride, n-tetradecyl salicylic anhydride, and positive Cetyl salicylic anhydride and the like. The monoamine compound may, for example, be aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-decylamine, n-decylamine or n-undecane. Amine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecyl Amine, n-icosylamine, and the like. The monoisocyanate compound may, for example, be phenyl isocyanate or naphthyl isocyanate.

The use ratio of the molecular weight modifier is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less based on 100 parts by weight of the total of the tetracarboxylic dianhydride and the diamine used in the synthesis of the polyamic acid.

[solution viscosity]

The polylysine and the polyimine obtained as described above preferably have a solution viscosity of 20 to 800 mPa·s, and more preferably have a solution viscosity of 30 to 500 mPa·s, when forming a solution having a concentration of 10% by weight.

The solution viscosity (mPa ‧ s) of the above polymer is a value measured at 25 ° C using a good solvent of the polymer and a 10 wt% polymer solution prepared using an E-type rotational viscometer.

<Other additives>

The liquid crystal alignment film of the present invention contains, as an essential component, a specific polymer of at least one selected from the group consisting of polylysine and polyamidene formed by dehydration and ring closure, and may contain other components as necessary. Examples of the other component include other polymers and tackifiers.

The other polymers described above can be used to improve solution properties and electrical properties. The other polymer is a polymer other than the specific polymer, and for example, the tetracarboxylic dianhydride is not contained in at least any one of the compound represented by the above formula (D-1) and the compound represented by the above formula (D-2). Polylysine obtained by diamine reaction (hereinafter referred to as "other poly-proline"), and polyimine formed by dehydration of the polyamine (hereinafter referred to as "other polyimine") , polyglycolate, polyester, polyamine, polyoxyalkylene, cellulose derivatives, polyacetal, polystyrene derivatives, poly(styrene-phenylmaleimide) derivatives, Poly(meth)acrylate and the like. Among them, other polyamines or other polyimines are preferred, and other polylysines are more preferred.

The proportion of the other polymer used is preferably 90% by weight or less, more preferably 85% by weight or less, based on the total amount of the polymer (referred to as the total amount of the specific polymer and other polymers, the same applies hereinafter). When the liquid crystal alignment agent of the present invention contains other polymers, the use ratio thereof is preferably 30% by weight or more, and more preferably 50% based on the total amount of the polymer, from the viewpoint of electrical properties of the formed liquid crystal alignment film. More than weight%.

The tackifier can be used for the purpose of improving the adhesion of the obtained liquid crystal alignment film to the surface of the substrate. Examples of the tackifier include a compound having at least one epoxy group in the molecule (hereinafter referred to as "epoxy compound"), a functional decane compound, and the like.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and neopentyl Alcohol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetrahydration Glyceryl-2,4-hexanediol, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl) Cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3-(N-allyl-N-glycidyl)amine Propyltrimethoxydecane, 3-(N,N-diglycidyl)aminopropyltrimethoxydecane, and the like.

The use ratio of the oxygen-containing compound as described above is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the total of the polymer.

The functional decane compound may, for example, be 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 2-aminopropyltrimethoxydecane or 2-aminopropylamine. Triethoxy decane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyl dimethyl Oxydecane, 3-guanidinopropyltrimethoxydecane, 3-guanidinopropyltriethoxydecane, N-ethoxycarbonyl-3-aminopropyltrimethoxydecane, N-ethoxylate Carbonyl-3-aminopropyltriethoxydecane, N-triethoxymethylidenepropyltriethylenetriamine, N-trimethoxymethylidenepropyltriethylenetriamine, 10-trimethyl Oxymethalin-1,4,7-triazadecane, 10-triethoxycarbamido-1,4,7-triazadecane, 9-trimethoxycarbamido-3 ,6-diazaindolyl acetate, 9-triethoxycarbamido-3,6-diazaindolyl acetate, N-benzyl-3-aminopropyltrimethoxydecane , N-benzyl-3-aminopropyltriethoxydecane, N-phenyl-3-aminopropyltrimethoxydecane, N-phenyl-3-aminopropyltriethoxydecane N-two ( Of extension ethyl) -3-aminopropyl trimethoxy Silane, N- bis (oxide extending aminoethyl) -3-aminopropyl triethoxy silane-like.

The use ratio of the functional decane compound as described above is preferably 2 parts by weight or less, more preferably 0.01 to 0.2 parts by weight, based on 100 parts by weight of the total of the polymer.

The liquid crystal alignment agent of the present invention is preferably constituted by dissolving at least one selected from the group consisting of poly-proline and polyimine, and other additives optionally mixed as needed in an organic solvent.

Examples of the organic solvent which can be used in the liquid crystal alignment agent of the present invention include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactone, and N,N-dimethylformamidine. Amine, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionic acid Ester, ethyl ethoxy propionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether (butyl cellosolve ), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene Alcohol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 3-butoxy-N,N-dimethylpropanamide, 3-methyl Oxy-N,N-dimethylpropanamide, 3-hexyloxy-N,N-dimethylpropionamide, and the like.

The solid content concentration in the liquid crystal alignment agent of the present invention (the ratio of the total weight of the components other than the solvent of the liquid crystal alignment agent to the total weight of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., preferably 1 to 10 The range of % by weight. That is, the liquid crystal alignment agent of the present invention can be applied to the surface of the substrate as described later, preferably by heating, to form a coating film of the liquid crystal alignment film, but when the solid content concentration is less than 1% by weight, the film thickness of the coating film If it is too small, it may be difficult to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by weight, the film thickness of the coating film is too large, and it may be difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases. Large, the coating properties may be deteriorated.

The range of the particularly preferable solid content concentration varies depending on the method employed when the liquid crystal alignment agent is applied onto the substrate. For example, when it is carried out by a spin coating method, the solid content concentration is particularly preferably in the range of 1.5 to 4.5% by weight. When the printing method is used, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, whereby the solution viscosity is in the range of 12 to 50 mPa·s. When the inkjet method is used, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, whereby the solution viscosity is in the range of 3 to 15 mPa·s.

The temperature at which the liquid crystal alignment agent of the present invention is prepared is preferably from 0 ° C to 200 ° C, more preferably from 20 ° C to 60 ° C.

<Liquid crystal display element>

The liquid crystal display element of the present invention has a liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention as described above.

A preferred mode of operation in the liquid crystal display device of the present invention is a lateral electric field type, but may be suitably used for a TN type, an STN type, or a VA type.

The liquid crystal display element of the present invention can be produced, for example, by the following steps (1) to (3). Step (1) The substrate used differs depending on the desired mode of operation. Steps (2) and (3) are the same for each mode of operation.

(1) First, the liquid crystal alignment agent of the present invention is applied onto a substrate, and then the coated surface is heated to form a coating film on the substrate.

(1-1) When manufacturing a TN type, STN type or VA type liquid crystal display element, a pair of two substrates on which a patterned transparent conductive film is formed is formed, and on each of the transparent conductive film forming surfaces, Preferably, the liquid crystal alignment agent of the present invention is applied by an offset printing method, a spin coating method, a roll coating method or an inkjet printing method, followed by heating each of the coated surfaces (preferably by preliminary heating (prebaking) and firing ( Post-baking) The two stages of heating are formed to form a coating film. In this case, as the substrate, for example, glass such as float glass or soda glass; polyethylene terephthalate, polybutylene terephthalate, polyether oxime, polycarbonate, or polycyclic ring can be used. A transparent substrate formed of plastic such as olefin. As the transparent conductive film provided on one surface of the substrate, a NESA film (registered trademark of PPG Corporation, USA) formed of tin oxide (SnO ₂ ), or indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) can be used. In order to obtain a patterned transparent conductive film, for example, a method of forming a pattern by forming a pattern-free transparent conductive film after photolithography, or a method of forming a mask having a desired pattern when forming a transparent conductive film, etc. get. When the liquid crystal alignment agent is applied, in order to make the surface of the substrate and the transparent conductive film and the coating film more adhesive, a functional decane compound or a functional titanium compound may be previously coated on the surface of the substrate on which the coating film should be formed. Wait for pre-processing.

The coated surface after the application of the liquid crystal alignment agent is then subjected to preheating (prebaking) and then fired (post-baking) to form a coating film. The prebaking conditions are, for example, 0.1 to 5 minutes at 40 to 120 ° C; the post-baking conditions are preferably 120 to 300 ° C, more preferably 150 to 250 ° C, preferably 5 to 200 minutes, more preferably 10 ~100 minutes. The film thickness of the formed coating film is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

(1-2) On the other hand, when manufacturing a horizontal electric field type liquid crystal display element, a surface on which a conductive film of a substrate on which a comb-shaped pattern is formed is formed and a side on which a conductive film is not provided The liquid crystal alignment agent of the present invention is applied separately, and then a coating film is formed by heating each of the coated surfaces.

The material of the substrate and the transparent conductive film used at this time, the coating method, the heating conditions after coating, the patterning method of the transparent conductive film, the pretreatment of the substrate, and the preferred film thickness of the formed coating film and the above (1- 1) Same.

In any of the above (1-1) and (1-2), the liquid crystal alignment agent of the present invention is a coating film which forms an alignment film by removing an organic solvent after coating, but in the liquid crystal alignment of the present invention When the polymer contained in the agent is polyaminic acid or a polyimine having both a quinone ring structure and a proline structure, it can be further heated after forming a coating film to carry out a dehydration ring-closure reaction to further sulfiliate A coating film is formed.

(2) When a VA liquid crystal display device is manufactured, the coating film formed as described above may be used as a liquid crystal alignment film as it is, but a rubbing treatment to be described later may be performed.

On the other hand, when manufacturing a TN type, STN type, or a lateral electric field type liquid crystal display element, the coating film formed as above is rubbed in a certain direction by a roll of a cloth formed of, for example, a fiber such as nylon, rayon, or cotton. deal with. Thereby, the alignment of the liquid crystal molecules can be imparted to the coating film to form a liquid crystal alignment film.

Then, the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention is treated, and by making the liquid crystal alignment film have different liquid crystal alignment energy in each region, the viewing angle property of the obtained liquid crystal display element can be improved, wherein the liquid crystal alignment film The treatment to be performed includes, for example, a process of irradiating a part of the liquid crystal alignment film with ultraviolet rays and changing a pretilt angle of a partial region of the liquid crystal alignment film, as described in Patent Document 3 or Patent Document 4, and as described in Patent Document 5, After a part of the surface of the liquid crystal alignment film is formed into a photoresist film, the treatment of removing the photoresist film is performed after rubbing treatment in a direction different from the previous rubbing treatment.

(3) The pair of substrates on which the liquid crystal alignment film is formed as described above are disposed oppositely by a gap (box gap), and the rubbing directions of the liquid crystal alignment films of the two substrates are orthogonal or antiparallel, and the two substrates are bonded together using a sealant. The surrounding portion is filled with liquid crystal in the cell gap divided by the surface of the substrate and the sealant, and the injection hole is sealed to constitute a liquid crystal cell. Then, a polarizing plate is bonded to the outer surface of the liquid crystal cell, and the polarizing direction is made uniform or orthogonal to the rubbing direction of the liquid crystal alignment film formed on each substrate, whereby a liquid crystal display element can be obtained.

In this case, as the sealant, for example, an epoxy resin containing a curing agent and an alumina ball as a separator can be used.

Examples of the liquid crystal include nematic liquid crystals and disc-type liquid crystals. Among them, nematic liquid crystals are preferable, and for example, a Schiff base liquid crystal, an oxidized azo liquid crystal, a biphenyl liquid crystal, or a phenyl ring can be used. Alkane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenyl cyclohexane liquid crystal, pyrimidine liquid crystal, two An alkane liquid crystal, a bicyclooctane liquid crystal, a cubic liquid crystal, or the like. Further, in these liquid crystals, a cholesteric liquid crystal such as cholestyl chloride, cholesterol phthalate or cholesterol carbonate may be further added; and the trade names "C-15" and "CB-15" (Merck) A chiral reagent sold by the company; a ferroelectric liquid crystal such as p-methoxybenzylidene-p-amino-2-methylbutylcinnamate or the like.

The polarizing plate to be bonded to the outer surface of the liquid crystal cell may be a polarizing plate formed by stretching a polyvinyl alcohol and arranging a polarizing film called absorbing iodine called "H film" with a cellulose acetate protective film. A polarizing plate formed by the H film itself.

[Examples]

Hereinafter, the present invention will be more specifically described by examples, but the present invention is not limited by the examples.

In the following synthesis example, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bis(aniline) was directly used as a product "Bisaniline M" manufactured by Mitsui Chemicals Co., Ltd.

Further, the solution viscosity of the polymer in each of the synthesis examples was a value measured at 25 ° C using an E-type viscometer.

<Synthesis Example of Polymer> Synthesis Examples 1 to 7 and Comparative Synthesis Examples 1 to 3

The amount of diamine and tetracarboxylic dianhydride shown in Table 1 was added to N-methyl-2-pyrrolidone in this order to form a solution having a monomer concentration of 15% by weight, and reacted at room temperature for 6 hours. A solution containing polylysine (PA-1)~(PA-7) and (PAR-1)~(PAR-3) was obtained. A small amount of each solution was taken, and N-methyl-2-pyrrolidone was added to form a solution having a polyglycine concentration of 10% by weight. The measured solution viscosity is shown in Table 1.

The amount of each half of these polyaminic acid solutions was ensured and used in the following Examples 1 to 6 and 12 and Comparative Examples 1 to 3, respectively.

Among the above polylysines, (PA-1) to (PA-5) and (PA-7) and (PAR-1) were subjected to a dehydration ring-closure reaction to form a polyimine.

Adding N-methyl-2-pyrrolidone to the remaining half of the above polyamic acid solution to form a solution having a polyglycine concentration of 6% by weight, and adding pyridine and acetic anhydride thereto, respectively, relative to the poly-proline After 1 mol of the valerine unit which has the molar ratio shown in Table 1, it heated up to 110 degreeC, and the dehydration ring-closing reaction was performed for 4 hours. After the dehydration ring closure reaction, the solvent of the system was replaced with a new N-methyl-2-pyrrolidone solvent (in this operation, the pyridine and acetic anhydride used in the dehydration ring-closure reaction were removed to the outside of the system), thereby obtaining 15% by weight, respectively. A solution of polyimine (PI-1)~(PI-5) and (PI-7) and (PIR-1). The ruthenium imidization ratio and solution viscosity of each polyimine contained in these polyimine solutions are respectively shown in Table 1, wherein the solution viscosity is a small amount of each solution to form a polyamidene concentration of 10% by weight. Determined by N-methyl-2-pyrrolidone solution.

These polyimine solutions were used in the following Examples 7 to 12 and Comparative Example 4, respectively.

In addition, in Table 1, the abbreviation of a diamine and a tetra-acid anhydride respectively has the following meaning.

<Diamine>

D-1: 4,4'-[1,3-phenylphenylbis(1-methylethylidene)]bis(aniline)

D-2: 1-(4-Aminophenyl)-1,3,3-trimethyl-1H-indan-5-amine

D-3: p-phenylenediamine

D-4: 4,4'-diaminodiphenylmethane

D-5: 4,4'-diaminodiphenyl ether

D-6: 3,3'-bis(tetramethyldioxane-1,3-diyl)-di(propylamine)

D-7: 3,5-diaminobenzoic acid

<tetracarboxylic dianhydride>

T-1: 2,3,5-tricarboxycyclopentyl acetic acid dianhydride

T-2: 1,2,3,4-cyclobutane tetracarboxylic dianhydride

T-3: pyromellitic dianhydride

T-4: 3,3',4,4'-biphenyltetracarboxylic dianhydride

Example 1 <Preparation of liquid crystal alignment agent>

In the polyglycine (PA-1)-containing solution obtained in the above Synthesis Example 1, γ-butyrolactone (BL), N-methyl-2-pyrrolidone (NMP), and butyl cellosolve (BC) were added. Then, an epoxy compound N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane as a tackifier is added, which is 10 with respect to 100 parts by weight (PA-1). A solution having a solvent ratio BL:NMP:BC=40:40:20 (weight ratio) and a solid content concentration of 4.0% by weight was formed in parts by weight. After the solution was thoroughly stirred, it was filtered using a filter having a pore size of 1 μm to prepare a liquid crystal alignment agent.

The liquid crystal alignment agent was used for evaluation as follows.

<Manufacture and evaluation of liquid crystal cell> [Manufacture of liquid crystal cell]

A liquid crystal cell for evaluation of liquid crystal alignment and dark state was produced as follows.

The above-prepared liquid crystal alignment agent was applied by a spin coater on a glass substrate having a chrome-plated thickness of 1 mm, and prebaked on a hot plate at 80 ° C for 1 minute, and then on a hot plate at 230 ° C. , after baking for 10 minutes, forming a film thickness of about 800 Coating film. A rubbing machine having a roll made of nylon was used for the formed coating film surface, and rubbing treatment was performed at a roll rotation speed of 1,000 rpm, a platen moving speed of 25 mm/s, and a pile press-in length of 0.4 mm to impart liquid crystal alignment energy. Then, the substrate was ultrasonically washed in ultrapure water for 1 minute, and dried in a clean oven at 100 ° C for 10 minutes to produce a substrate having a liquid crystal alignment film on the surface of the comb-shaped chrome electrode.

In contrast, a coating film of a liquid crystal alignment agent was formed on one surface of a glass substrate having a thickness of 1 mm without an electrode, and after rubbing treatment, washing and drying were performed, and a substrate having a liquid crystal alignment film was produced on one surface.

These substrates are formed into a pair, and an epoxy resin adhesive having an alumina ball having a diameter of 5.5 μm is applied to the outer edge of the surface of the substrate having the rubbed liquid crystal alignment film, and then the two substrates are opposed to each other through the gap. The rubbing directions in the liquid crystal alignment films are antiparallel, and the outer edges are pressed in contact to cure the adhesive. Next, a nematic liquid crystal (MLC-2042, manufactured by Merck Co., Ltd.) was filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an acrylic photocurable adhesive to produce a horizontal electrolytic cell.

[Evaluation of the liquid crystal cell] (1) Evaluation of liquid crystal alignment

The liquid crystal cell manufactured above was observed using a polarizing microscope. In this case, the evaluation that the light transmission was not confirmed at all was "excellent" in the liquid crystal alignment, and the evaluation of only the light transmission was confirmed to be "good" in the liquid crystal alignment, and the evaluation of the light transmission was confirmed as the liquid crystal alignment. "In this case, the liquid crystal alignment of the liquid crystal cell is "excellent".

(2) Evaluation of dark state

The liquid crystal cell manufactured above was sandwiched by a pair of polarizing plates, and the degree of dark state when no voltage was applied was examined.

When the polarizing plate and the liquid crystal alignment film are arranged in a rubbing direction orthogonal to the polarizer, the light transmittance is 0%, and the rubbing direction of the pair of polarizing plates and the liquid crystal alignment film is arranged in parallel with the polarizer, and the light is transmitted when a voltage is applied. When the rate is 100%, the pair of polarizing plates and the liquid crystal alignment film are bonded in parallel with each other in the rubbing direction of the liquid crystal alignment film, and the light transmittance in a state where no voltage is applied is examined. When the light transmittance is less than 0.1%, the dark state is "excellent"; when it is 0.1% or more and less than 0.2%, the dark state is "good"; when it is 0.2% or more, the dark state is "not good".

In addition, the evaluation of the (2) dark state is a liquid crystal cell which is "excellent" or "good" in the evaluation of the liquid crystal alignment property (1), and which exhibits a substantially suitable liquid crystal alignment property, and further high precision and strictness. The evaluation is an evaluation of an indicator of display quality of a high image quality level in recent years.

(3) Evaluation of afterimage

In addition to the above [manufacture of a liquid crystal cell], a glass substrate having a comb-shaped transparent conductive film pattern formed of chromium having two systems is formed in a pair with a glass substrate having no transparent conductive film, and has a comb-like transparency. The liquid crystal cell was produced in the same manner as in the above [manufacture of a liquid crystal cell], except that the liquid crystal alignment agent was applied to the transparent conductive film of the substrate of the conductive film and the other substrate. Further, a polarizing plate is bonded to the outer surface of the substrate of the liquid crystal cell and the rubbing direction of the liquid crystal alignment film in parallel with the polarizing plate to fabricate a liquid crystal display element.

A schematic diagram showing a transparent electrode pattern constituting the above glass substrate is shown in Fig. 1.

The liquid crystal display element produced above was placed in an environment of 25 ° C and 1 atm, and a voltage of 3.5 V of an alternating current voltage and a direct current voltage of 5 V was applied to the electrode A without applying a voltage to the electrode B. Thereafter, a voltage of 4 V of alternating current was applied to both of the electrodes A and B. The time from when the voltage of 4 V of alternating current was applied to the two electrodes was reached, and the time until the difference in light transmittance between the electrodes A and B disappeared. In addition, when the time is 300 seconds or less, the afterimage property is "excellent", and when it is more than 300 seconds and 500 seconds or less, it is generally evaluated that the afterimage property is "good", and the shorter the time, the better.

Examples 2 to 12 and Comparative Examples 1 to 4

A liquid crystal alignment agent was prepared in the same manner as in Example 1 except that the polymer-containing solution shown in Table 2 was used as the polymer solution, and a liquid crystal cell was produced and evaluated. Further, in Example 12, two polymers were mixed and used as a polymer. Here, 10 parts by weight of the tackifier is used with respect to 100 parts by weight of the total of the polymer.

The evaluation results are shown in Table 2.

1 is a schematic view showing a configuration of two transparent conductive film patterns of a liquid crystal display element produced by evaluation of the residual image properties in the examples and the comparative examples.

Claims (5)

A liquid crystal alignment agent comprising at least one polymer selected from the group consisting of polylysine and polyamidiamine, wherein the polymer has the following formula in at least a part of its molecule ( 1) and (2) respectively represent the structure; In the formula (1), R ¹ each independently represents an alkyl group having 1 to 6 carbon atoms, and R ² each independently represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, a cyano group, a hydroxyl group or a carboxyl group. n is an integer of 1 to 10, a each independently represents an integer of 0 to 4, "*" represents a linkage; in the formula (2), R ³ is an alkyl group having 1 to 6 carbon atoms, and R ^{4 is} independently The ground represents an alkyl group having 1 to 6 carbon atoms, a halogen atom, a cyano group, a hydroxyl group or a carboxyl group, b is an integer of 0 to 5, c is an integer of 0 to 4, and d is an integer of 0 to 3, "*" Indicates the connection key. The liquid crystal alignment agent of claim 1, wherein the polymer is a poly-proline which is obtained by reacting a tetracarboxylic dianhydride with a diamine, and a polyimine formed by dehydration of the polyglycolic acid. At least one selected from the group consisting of a compound represented by the following formula (D-1) and a compound represented by the following formula (D-2). R ¹ , R ² , n and a in the formula (D-1) are respectively the same as defined in the above formula (1); respectively, R ³ , R ⁴ , b, c and d in the formula (D-2) The definitions in the above formula (2) are the same. The liquid crystal alignment agent of claim 2, wherein the tetracarboxylic dianhydride comprises at least one selected from the group consisting of aromatic tetracarboxylic dianhydrides, and is selected from the group consisting of aliphatic dicarboxylic anhydride structures or alicyclic binary groups. At least one of a tetracarboxylic dianhydride having a carboxylic anhydride structure. The liquid crystal alignment agent of claim 2 or 3, wherein the diamine further comprises p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4 At least one selected from the group consisting of 4'-diaminodiphenyl ether and 3,3'-(tetramethyldioxane-1,3-diyl)di(propylamine). A liquid crystal display element comprising a liquid crystal alignment film formed of the liquid crystal alignment agent according to any one of claims 1 to 4.